The long-term objectives of this proposal are to understand the regulation of ribosomal protein synthesis in yeast. We have chosen to study this problem in yeast because of the simplicity of the organism and the availability of genetic, physiological, and molecular approaches. We will analyze regulation in vivo by measuring beta-galactosidase (lacZ) activity from ribosomal protein beta-galactosidase fusions introduced into yeast. These polypeptide fusions should reflect the normal regulation of ribosomal protein genes. Once the regulation of the fusions has been understood, the ribosomal protein genes will be mutated in vitro to define the DNA sequences responsible for this regulation. Cell mutants will also be isolated to define proteins which act in trans to regulate ribosomal protein synthesis. A similar analysis will be applied to splicing. DNA mutants will be generated in vitro to analyze the requirements for splicing. Wild type and mutant intron-containing fusions will be utilized to generate mutants in splicing enzymes. These latter studies are pointed towards defining the requirements for splicing in yeast and the role of splicing in ribosomal protein regulation. A similar goal exists for the generation of an intronless rp 51 gene; Can it replace the normal rp 51 gene? While all of these studies will be done in yeast, we expect that many of the results will be applicable to ribosomal protein regulation in metazoans. Since the neoplastic state is characterized by unregulated growth and since ribosomal proteins are growth regulated, their relationship to the health sciences is strong.